'No suitable backend found' error

Thanks for your bug report. You've probably run into a serious bug in the nVidia backend. Could you please try the following at a command prompt and report what the output is exactly?
  cd /usr/share/disper/src
  python -c 'from nvidia import *; NVidiaControl()'

I don't get any output at all...

cacraft@cacraft-MOBL /usr/src/software/disper/src $ python -c 'from nvidia import *; NVidiaControl()'
cacraft@cacraft-MOBL /usr/src/software/disper/src $

That's good. I should have asked to try this as well
  cd /usr/share/disper/src
  python -c 'from switcher.swnvidia import *; NVidiaSwitcher()'
I suspect that does give some output.

Here's the output:

cacraft@cacraft-MOBL /usr/share/disper/src $ python -c 'from switcher.swnvidia import *; NVidiaSwitcher()'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "switcher/swnvidia.py", line 19, in <module>
    import xrandr
  File "xrandr/__init__.py", line 41, in <module>
    from ctypes import *
  File "/usr/lib64/python2.5/ctypes/__init__.py", line 20, in <module>
    raise Exception, ("Version number mismatch", __version__, _ctypes_version)
Exception: ('Version number mismatch', '1.0.3', '1.0.2')

Thanks, that narrows the problem to the python xrandr bindings and/or ctypes. There may be a problem with your python ctypes installation. It looks like a bug #285411; could you please verify that it is the case by running the following:
   grep ^__version__ /usr/share/pyshared/ctypes/__init__.py
   strings /usr/lib/python*/lib-dynload/_ctypes.so | grep 1\.\0\.
if these numbers are different it is the culprit.

Still the problem doesn't occur here although these version numbers are different with me. The output of the following commands might help as well
  python -v -c 'import ctypes'
If that doesn't fail, please try
   cd /usr/share/disper/src
  python -v -c 'import xrandr'

They are different:

cacraft-MOBL disper # grep ^__version__ /usr/lib64/python2.5/ctypes/__init__.py
__version__ = "1.0.3"
cacraft-MOBL disper # strings /usr/lib64/python2.5/site-packages/_ctypes.so | grep 1\.\0\.
1.0.2

cacraft-MOBL disper # python -v -c 'import ctypes'
# installing zipimport hook
import zipimport # builtin
# installed zipimport hook
# /usr/lib64/python2.5/site.pyc matches /usr/lib64/python2.5/site.py
import site # precompiled from /usr/lib64/python2.5/site.pyc
# /usr/lib64/python2.5/os.pyc matches /usr/lib64/python2.5/os.py
import os # precompiled from /usr/lib64/python2.5/os.pyc
import errno # builtin
import posix # builtin
# /usr/lib64/python2.5/posixpath.pyc matches /usr/lib64/python2.5/posixpath.py
import posixpath # precompiled from /usr/lib64/python2.5/posixpath.pyc
# /usr/lib64/python2.5/stat.pyc matches /usr/lib64/python2.5/stat.py
import stat # precompiled from /usr/lib64/python2.5/stat.pyc
# /usr/lib64/python2.5/UserDict.pyc matches /usr/lib64/python2.5/UserDict.py
import UserDict # precompiled from /usr/lib64/python2.5/UserDict.pyc
# /usr/lib64/python2.5/copy_reg.pyc matches /usr/lib64/python2.5/copy_reg.py
import copy_reg # precompiled from /usr/lib64/python2.5/copy_reg.pyc
# /usr/lib64/python2.5/types.pyc matches /usr/lib64/python2.5/types.py
import types # precompiled from /usr/lib64/python2.5/types.pyc
import _types # builtin
# /usr/lib64/python2.5/warnings.pyc matches /usr/lib64/python2.5/warnings.py
import warnings # precompiled from /usr/lib64/python2.5/warnings.pyc
# /usr/lib64/python2.5/linecache.pyc matches /usr/lib64/python2.5/linecache.py
import linecache # precompiled from /usr/lib64/python2.5/linecache.pyc
import encodings # directory /usr/lib64/python2.5/encodings
# /usr/lib64/python2.5/encodings/__init__.pyc matches /usr/lib64/python2.5/encodings/__init__.py
import encodings # precompiled from /usr/lib64/python2.5/encodings/__init__.pyc
# /usr/lib64/python2.5/codecs.pyc matches /usr/lib64/python2.5/codecs.py
import codecs # precompiled from /usr/lib64/python2.5/codecs.pyc
import _codecs # builtin
# /usr/lib64/python2.5/encodings/aliases.pyc matches /usr/lib64/python2.5/encodings/aliases.py
import encodings.aliases # precompiled from /usr/lib64/python2.5/encodings/aliases.pyc
# /usr/lib64/python2.5/encodings/utf_8.pyc matches /usr/lib64/python2.5/encodings/utf_8.py
import encodings.utf_8 # precompiled from /usr/lib64/python2.5/encodings/utf_8.pyc
Python 2.5.2 (r252:60911, Nov 25 2008, 10:20:37)
[GCC Intel(R) C++ gcc 4.1 mode] on linux2
Type "help", "copyright", "credits" or "license" for more information.
import ctypes # directory /usr/lib64/python2.5/ctypes
# /usr/lib64/python2.5/ctypes/__init__.pyc matches /usr/lib64/python2.5/ctypes/__init__.py
import ctypes # precompiled from /usr/lib64/python2.5/ctypes/__init__.pyc
dlopen("/usr/lib64/python2.5/site-packages/_ctypes.so", 2);
import _ctypes # dynamically loaded from /usr/lib64/python2.5/site-packages/_ctypes.so
# /usr/lib64/python2.5/struct.pyc matches /usr/lib64/python2.5/struct.py
import struct # precompiled from /usr/lib64/python2.5/struct.pyc
dlopen("/usr/lib64/python2.5/lib-dynload/_struct.so", 2);
import _struct # dynamically loaded from...

As a workaround I'll create an XRandR fallback method that calls the xrandr binary instead of using ctypes bindings.